House and Senate negotiators, in a rare bipartisan act, announced a budget agreement Tuesday designed to avert another economy-rattling government shutdown and to bring a dose of stability to Congress's fiscal policy-making over the next two years.

Sen. Patty Murray (D., Wash.) and Rep. Paul Ryan (R., Wis.), who struck the deal after weeks of private talks, said it would allow more spending for domestic and defense programs in the...